Guards and grilles have been used for centuries to protect windows and doors of buildings from unauthorized entrance, as well as to enhance the appearance of buildings. The practice of placing such guards permanently on buildings had the obvious disadvantage of precluding egress therethrough in an emergency situation, as many municipal ordinances now recognize. Guards which provide a release activated from the inside of a building often had the drawbacks of complicated mechanisms for such release, including springs, flexible cables, and various parts which, once installed, were virtually inaccessible for inspection, cleaning, lubrication, or replacement. The failure or jamming of any of these mechanisms, coupled with an emergency exit situation, could have grievous and fatal results.
In addition, the security aspect of such guards was similarly jeopardized by the open exposure of the hinging and locking components. A guard utilizing even an effective locking device could be defeated by cutting the hinging or locking components. Guards which expose these components to external scrutiny all run the risk of defeat and unauthorized penetration into the protected premises by means as simple as a hacksaw.
A further pejorative aspect of the prior art is that prior guards were not capable of being removed from the wall, as might be desired for cleaning, ease in replacement, or in the case of seasonal usage only, without involved and costly procedures.
Examples of prior art deficient in the ways described (i.e., requiring spring mechanisms and further having exposed hinges and locking devices, etc.) are shown in U.S. Pat. Nos. 3,843,176, 3,921,334, 4,055,360, 4,057,935, 4,070,048, and 4,263,747. None of these inventions, also including those described in U.S. Pat. Nos 4,249,345 and 4,274,228 allow for the removal of the guard without an involved and costly procedure.